Software products are increasingly used to perform a wide variety of functions. Goals and objectives of the software products may be realized by defining quality requirements associated with the software products. The quality requirements may include functional as well as non-functional requirements of the software products. The functional requirements describe what the software product has to do. The non-functional requirements are those requirements which stipulate how well the software programs does, such as security, performance, usability, and reliability of the software products. The non-functional requirements play a crucial role during development of the software products.
Various models and frameworks have been developed as an attempt for eliciting the non-functional software requirement for a software product to be developed. These frameworks and models are designed to facilitate in identifying the functional and non-functional requirements applicable for the software products.